1. Field of the Invention
The present invention relates to a sealed lamp device such as a metal halide lamp which is one type of high voltage discharge lamps, and a projector using the same.
2. Description of Related Art
In related art, a light source unit configured by combining a concave mirror and a discharge lamp burner such as an extra-high pressure mercury lamp and a metal halide lamp is used as a lighting source for a projector.
Recently, a so-called sealed lamp device, in which a front plate made of a translucent material is placed at a front opening of the concave mirror on the light-emitting side, is typically used.
The discharge lamp burner radiates not only light but also a large amount of heat. Accordingly, longer use cause overheat of the discharge lamp burner or the vicinity thereof, and may result in burst or loss of clarity of the burner and breakage of inner surface of the concave mirror.
The sealed lamp device has advantages in preventing burst sound from leaking outside and broken pieces from dispersing outside even if the discharge lamp burner accommodated therein blows out. In addition, the sealed lamp device has advantages in preventing luminance decrease due to entering of dust or mote contained in ambient air.
However, in view of emission efficiency and life of the discharge lamp burner, temperature of the discharge lamp burner needs to be in a predetermined range. Accordingly, air cooling using a fan such as a sirocco fan or axial fan is conducted to blow air to the discharge lamp burner. A technology similar to such related art is disclosed in Japanese Patent Application Publication No. JP 2001-183746.